Function mergeRunOptions

packages/effect/src/ManagedRuntime.ts:297–308

(options?: O)

    onFiberStart: Fiber.runIn(scope)
  }
  const mergeRunOptions = <O extends Effect.RunOptions>(options?: O): O =>
    options
      ? {
        ...options,
        onFiberStart: options.onFiberStart ?
          (fiber) => {
            defaultRunOptions.onFiberStart!(fiber)
            options.onFiberStart!(fiber)
          } :
          defaultRunOptions.onFiberStart
      }
      : defaultRunOptions as O
  let buildFiber: Fiber.Fiber<Context.Context<R>, ER> | undefined
  const contextEffect = Effect.withFiber<Context.Context<R>, ER>((fiber) => {
    if (!buildFiber) {